1. Field of the Invention
This invention relates to a device for regulating the temperature of material in a container which is surrounded by a heat conducting medium.
2. Prior Art
Many materials keep their desired properties only when at a certain temperature. If they are too hot or too cold, they lose their advantageous properties and often become unusable. The sensitivity of materials to temperature variations in the usual range of ambient temperatures from about -40.degree. C. to +50.degree. C. is very diverse. Building materials such as wood, stone or glass only change their properties very little with varying temperatures, while liquid materials with freezing points in the temperature range mentioned change their properties very significantly. Medicaments, and in particular fluid medicaments of high molecular weight, assume a special place among temperature sensitive substances, so that it is most desirable that they are stored at a certain constant temperature. For some medicaments, but also for some other products, it is often important that these products are continuously in the right temperature conditions--even during the transportation of them. In particular, diabetics need properly cooled insulin with which to inject themselves or with which to be injected. It is therefore advantageous to have cooling boxes for insulin ampoules which can be taken in a car or otherwise on one's travels.
A small cooling cell is already known for motor vehicles with air conditioning, which is particularly suitable for taking food, refreshment drinks, the cell having a small space for forced cooling of medicaments and such like, (German Patent Application Laid Open No. 3 004 716). A disadvantage with these cooling cells is that they can only be used in motor vehicles with air-conditioning. Furthermore, a thermo-electric cooling apparatus is known for motor vehicles, having a thermally-insulated chamber cooled by the cold side of an electro-thermic battery, while the hot side of this battery is in a forced air stream, (Soviet Union Pat. No. 615 337). This cooling apparatus is therefore not particularly suitable for use in means of transport.
A cooling apparatus which has a relatively small weight and is transportable is also already known (German accepted Patent Application No. 1 214 254). This cooling apparatus, which can also be used in motor vehicles or on a camp-site, has Peltier cooling elements as a cooling means. However, this apparatus actually has neither a particular internal arrangement nor means which make it suitable for transport.
A Peltier block made up of many elements assembled together is also known (German Patent Application Laid Open No. 1 401 529). On the heat-emitting and/or the heat absorbing side of this block there are arranged receptacles of anodized aluminium. It is however not stated in this Specification whether, and if so how, the Peltier block can be used in a portable cooling box.
The use of a Peltier block in association with a cooling box which is suitable for a motor vehicle is also already known (German Utility Model No. 81 03 411). This cooling box is intended for the cooling of medicaments and has a heat conducting plate on the bottom of a housing to which, inside the apparatus, the Peltier element has its hot surface in heat-conducting contact. The surface of the Peltier element directed away from the plate is in heat-conducting contact with a heat conducting material block, in which at least one recess is provided for the reception of medicaments. It is not obvious how this known cooling box can be fixed in a motor vehicle, whether it can be carried, and how the medicaments are put in it.
A device with which milk bottles or the like can be thermo-electrically heated or cooled and in which details of the reception space for radially-cooled goods are shown, is also know (U.S. Pat. No. 2,959,925). In any event, this device is hardly transportable and is thus barely suitable for use in the cooling of medical materials in a car or during vacation.
A special electro-thermic cooling arrangement provided for the cooling of insulin ampoules which is constructed in a compact and transportable form is also know (U.S. Pat. No. 3,713,302). This cooling arrangement can be operated for several days by means of electrical batteries, without these batteries needing to be changed in the meantime. Nevertheless, this known cooling arrangement can only take one insulin flask. In addition, the removal of the flask is somewhat laborious, as a sliding cover has to be removed.
Finally, an arrangement is also known with which it is possible to use a Peltier element, both as a heating and as a cooling element, which serves to adjust the temperature of a medicament. The flask containing the medicament is nevertheless accessible only with difficulty (U.S. Pat. No. 3,858,106).